1. [多选题]With regard to Ethernet media access methods, which of the following are true?(Choose all that apply.)
A. A device waits for an electronic signal before transmitting.
B. A device listens and waits until the media is not busy before transmitting.
C. All devices on an Ethernet segment see data that passes on the network medium.
D. Only the sender and the receiver devices see data that passes on the network medium.
E. Ethernet networks allow you to configured devises with higher transmission priority.
2. [单选题]OSPF骨干区的区域编号为（）
A. 0.0.0.1
B. 255
C. 0.0.0.0
D. 255.255.255.255
3. [多选题]In which Spanning-Tree states does a switch port learn MAC addresses? (Select two)
A. Blocking
B. Listening
C. Forwarding
D. Learning
E. Relaying
4. [多选题]Why is full-duplex Ethernet superior to its single-duplex counterpart? (Select two answer choices.)
A. It uses inexpensive hubs
B. It operates without collisions
C. It operates on switches
D. It provides faster data transfer
E. It utilizes fewer wiring pairs
5. [单选题]两个VLAN之间要想通信，应该使用的设备是（）
A. 集线器
B. 二层交换机
C. 路由器
D. PC机
